Sling backpack



FIG. 1 is a perspective view.

FIG. 2 is a front view.

FIG. 3 is a rear view.

FIG. 4 is a left side view.

FIG. 5 is a right side view.

FIG. 6 is a top view; and,

FIG. 7 is a bottom view.

The broken lines in the figures are for the purpose of illustrating portions of the sling backpack and stitching and form no part of the claim. 

CLAIM The ornamental design for a sling backpack, as shown and described. 